Digital video can be used for various applications, including, for example, video conferencing, high definition video entertainment, video advertisements, or sharing of user-generated videos. Digital video streams may represent video using a sequence of frames or still images. Each frame can include a number of blocks, which in turn may contain information describing the value of color, brightness or other attributes for pixels. A digital video stream can contain a large amount of data and consume a significant amount of computing or communications resources of a computing device for processing, transmitting or storing of the video data. Various approaches have been proposed to reduce the amount of data in video streams, including compression and other encoding techniques.